Method of annealing



July 21, 1925.

' T. F. BAILY METHOD 0F ANNEALING Filed March 18, 1924 KMNHWIH -HMH u HWHHOM u NNN.-

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||||||lp||HWw|p Ul In m Patented July 21,' 1925 f THADDE'US, F. BILY, EALLIANCE, OHIO.

METHOD F ANNEALING.

Application 'led March 18, 1924. Serial No. 700,002,

whereby the heat from a hood which is at a high temperature may he utilized in heating other hoods which may he operating at the same time at a lower temperature, while in the same manner the cooling action of material in certain of the hoods may be accelerated hy circulating the inert gas Jfrom a hood which is nearly cooled, to a hood oli/a higher temperature.

'llhe process embodying the invention may loe attained with an apparatus suchas illustrated in the accompanying drawing, in

which- Figure 1 is a diagrammatic plan yiewiot1 f a plurality of annealing hoods with means for circulating an inert gas through certain of the hoods for the purpose of utilizing heat from one hood to assistin raising the temperature of another hood and to accelcrate the cooling of certain of the hoods;

Fig. 2, a similar view showing a later poi" i sition of the apparatus; and

f `Fig. 3, a sectional View ot a heater adapted for combustion to superheat the inert gas in order to maintain the temperature of the materials in the soaking hood and to raise the temperature of thematerials in the hood which is nishing heating.

Similar numerals refer to similar parts throughout the drawing.

A plurality ot annealing hoods are indicated conventionally at d, these hoods ,heing arranged in a series and numbered from 1 to 7 inclusive, the hood numbered 1 losing shown at t-he extreme left, the other hoods heing arranged in order from left to right. '1n carrying out the invention, each of the hoods A may he connected with a pair of spaced passages B and C torming an inlet and outlet respectively tor each hood, whereloy the inert gas may he circulated through the/hoods as will be later described.

,/lln the position shownv in Fig. 1, the hood 1 is heating from600o to 900 and the hood '2 is just starting to heat to 600. rlhe hood 3 in this position is cold and in condition for loading or unloading.' rlhe hood d'is coo'lingdown from 900 to 600o and the lfood 5 has just started to cool from 14:00o to 900., The hood 6 is soaking at an even temperature or'u 14000 andthe hoodV 7' is linishing the heating from 900O to 14:00".

ln this position of the apparatus, the hood- 3 which is cold and in position for loading or unloading, is disconnected from the other hoods as well as the hood 6., which is soaking at the maximum temperature, and the hood 7 which is nishing the heating, preparatory to soaking at the maximum ternperature. l

Each of' the hoods 0 and 7 is provided with a connecting pipe D connectingV the passages B and C thereof, whereby these two may he cut out of communication with the general circulating system.

A duct E is located parallel to the ends of the hoods and provided at intervals with outlets F by means of which any of the hoods may be connected thereto.

ln the position shown in hig. 1, the pas-- sage B of the hood 1 which is heating from 600o to 9100o is connected to the duct E as by a detachable pipe Gr and the passage C ot the hood 5 which is cooling from 1400o toA 900, is connected to the other 4end of the duct as hy the detachable pipe lai.

The passage C olf the, hood 1 is connected to the passage B oitL the'hood 2 as by a sinnlar detachable pipe l, the passage C ot the y,

hood 2 being connected to the passage B ot the hood l hy a, detachahle pipe section d in which is located a tan lil., v

The passage C of the hood l is connected to the passage B of the hood ahy a detachahle pipe section L. A complete circulation is thus provided through the hoods 1, 2,4 and 5, returning from the hood 5 to the hood 1 through the duct E. in inert gas may he thus circulated through the hoods 1, 2, d and 5 by means of the 'fan K in the direction of the arrows shown in Fig,l 1. A

rllhe hoods may he heated in any desired manner and for the purpose of illustration, electrodes M are shown which may he detachahly connected to the electric wires hl, ln the position shown in Figa 1, only the electrodes of the hoods d and 7 are connected in the circuit,l

liristead ot using the electric heating icc p ica means for heating the hoods 'which are soaking and finishing heating, the heater Q such as shown in Fig. 3, which may be in the form of a portable gas heating device, may be detachably connected to these hoods for heating the inert gas before it passes through these hoods.

A separate fan or other means may be used to provide the necessary circulation or these hoods may be connected with the general circulating system. It may also be desirable to operate this equipment when using the electric heating means for the soakingi and finishing heating hoods by having these hoods in the general circulating system.

The hoods l and 2 are heated to temperay tures 'of 900 and 600 respectively by the heat which is withdrawn from the hood 5, which has started to cool, while the hood i is cooled from 900 down to 600 bydrawing the gas directly from the hood 2 at A not over 6000 and forcing it into. the hood 4.

ln Fig. 2 is sho-wn the next .position of the operation. At this point the hood l is finishing heating from 900 to 1400, the electrodes thereof being connected to the electric circuit.

This hood, therefore may be cut out of communication with the other hoods, a detachable pipe section l) connecting the passages B and C thereof. The temperature in the hood 2 has also been raised andthis hood is now heating from 600 to 900, the passage B thereof being connected ,by the pipe section G with the duct E.

The hood 3 has been loaded and is heating up to 600 and is connected by the pipe section l to the hood 2. The hood 4l has cooled and is in position for unloading and loading and is out out from communication with the other hoods.

The pipe section J containin the fan K connects the passage C of the hood 3 with the passage B of the hood 5, which is cooling from 900 to 600 and the passage C of this hood is connected by the pipe section L with the passage B of the hood 6, which has started to cool from 1400o to 900.

The passage C of the hood 6 is connected by the pipe section H with the other end of the duct E, whereby a complete circulation of inert gas is produced throughl thel hoods 2, 3, 5 and 6 in the samev manner` as above described regarding the hoods 1,2, 4; and 5.

The hood 7 has reached the maximum heat and is soaking, and the passages Bv and C thereof may be connected together by the pipe-section D, cutting this hood out of communication with the hoods throu h which the inert gas is being circulated. r this hood maybe put into a separate communicat'ing system, as above described.

attacca In this position the hoods 1 and 7 may be heated as by the electrical connection of the electrodes therein to' the'line wires, or by the gas heater, While all of the other hoods will be disconnected from said Wires or heater, only the Waste heat being circulated through the hoods.

lt will be understood that this opera-tion may be carried on indefinitely in the manner above described, the annealing operation progressing from left toy/right through the several hoods.

Although the best results are probably obtained by circulating the inert gas through the hoods in the manner illustrated, it may be desirable to also communicate the hoods which lare finishing heating and soaking in the general circulation of inert ges.

l claim:-

l. The method of annealing which consists in circulating gas through hoods of a high temperature and through hoods of a lower temperature to raise the temperature of material in the last named hoods.

2. The method of annealing which consists in circilating gas through hoods of a low temperature and through hoods of a higher temperature to lower the temperature 'of material in the last named hoods.

3. The method of annealing which consists in circulating an inert gas. through hoods of low mperatures which are heating and then through hoods of higher temperatures which are cooling.

4. The method of annealing whichv consiste in circulating an inert gas through a series of hoods of high temperatures which are cooling and then through a series of hoods bf lower temperatures which are heating.

5. 'lhe method of annealing which ronsists in circulating an inert gas through hoods which have reached or passed theiru maximum temperature into hoods that have not reached their maximum temperature, the heat thus absorbed from the material having reached its maximum temperature being used in raising the temperature of the material that has not reached yits maximum temperature.

6. The method ofA annealing which ccnsists in circulating an inert gas through hoods which have reached or paed 'their maximum temperature into hoods that have c not reached their maximuml temperature, the

heat thus absorbed from. the material having reached its maximum temperature being used in raising the temperature ofthe I ature.

7. In a series of annealing hoods, .means for circulating inert gas through a series of hoods that have reached the annealing temperature, thereby cooling said hoods and the contents and means for forcing said heated inertgas through hoods containing n'iaterial that is being brought up to temperature, the heated gases giving up their heat to the hoods that have not yet reached their maximum temperature.

8. The method of annealing which consists in circulating gas through a series of hoods of successively lower temperatures which are heating and then through a series of hoods of successively higher temperatures which are cooling. Y

9. The method of annealing which consists in circulating gas through a series of hoods of successively higher temperatures which are cooling and then through a series of hoods of successively lower temperatures which are heating.

In testimony that l claim the above, I have hereunto subscribed my name.

THADDEUS F. BAILY. 

